Honyaki patination/etching

Hi everyone, I wanted to start a little discussion about honyaki knives and aesthetics. Lots of western makers have tried their hand at differentially hardened knives. In my opinion some are achieving incredible results, others not so much. These are just my tastes though, there's no real correct or incorrect way to make them.
The term Honyaki translates to "authentically forged" or "this grilled" if you use google translate (don't do that). This is a reference to how Nihonto swords are made. Although there are one ore two similarities between Honyaki knives and some Japanese swords, in almost every way they are completely different. The materials, tools, temperatures and techniques used and their purpose and results on the finished product are not at all the same.
Basically all Honyaki knives are not made the way Nihonto is, so it's a bit of a misnomer already. They are made of steel, they are sharp, and most have squiggly lines running the length of the blade. That's where the similarities end.
As I ramble - next topic. Ferric Cloride!
To get good contrast, usually such a long etch is used that results in a mate, dull surface. The colors are inverted compared to the way Nihonto is etched most commonly with Nugui and a lot of character in the "Hamon" is lost.
One could argue Hamon is also not appropriate for describing that line on Honyaki because it roughly translates to "edge line" but could not be farther from the edge of the knife on most Honyaki.
I recently found Goddars Silver Polish to produce similar results and coloration to Nugui used on Nihonto. It is a little bit too fast acting for me so usually I'll water it down to 10% it's original strength before wiping the clean blade down with it.
I'll post some pics of my results with it below.
What are your thoughts on Honyaki knives? (The thousand dollar specimens coming out of Sakai, and also the more interpretive ones made by some of the vendors on this forum.)

Correction- the product I used is actually called Goddard's silver dip

Interesting, I would love to see your pics. Also, have you use the polish product by the same brand?

Cool topic and very interested as well. I have honyakis from konosuke and ikeda and just love them. I usually just bring my knives to Jon to clean up but trying it out myself sounds pretty fun, just never knew where to start with honyakis.

So basically you would not reccomend using nugui for Honyaki? Just curious because I have been considering getting some from Namikawa to polish a Honyaki gyuto and yanagiba both Shirogami. If you were to use nugui which would you use? I'm less concerned with maintaining the original mirror finish and more interested in trying something new and cool.

v647c said:

So basically you would not reccomend using nugui for Honyaki? Just curious because I have been considering getting some from Namikawa to polish a Honyaki gyuto and yanagiba both Shirogami. If you were to use nugui which would you use? I'm less concerned with maintaining the original mirror finish and more interested in trying something new and cool.

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Not at all, I've just never tried it. I think it would be a really cool idea

Here is an example of the patination I was mentioning earlier.
This is the best picture I could do in my poorly lit room, it's pretty accurate except the brown tint on the soft steel near the spine

That's what you got from the etch Jon? It looks pretty nice to me. Does it preserve the contrast between soft and hard steel after use?

Not all steels will readily display and accented hamon line even if they are "clay back" processed. O1 carbon tool steel is one example (but not the only example) of a hamon-shy steel. This is not to say o1 does not produce a hamon, it just has a tendency to be a little more subdued. One way to bring out the hamon line is to polish the entire blade carefully, then etching this blade in boiling vinegar, then polishing it again carefully with the hamon line's representation in mind.

jklip13 said:

Here is an example of the patination I was mentioning earlier.

This is the best picture I could do in my poorly lit room, it's pretty accurate except the brown tint on the soft steel near the spine

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Patina from use develops basically the same way as without the silver polish treatment

tsuriru said:

Not all steels will readily display and accented hamon line even if they are "clay back" processed. O1 carbon tool steel is one example (but not the only example) of a hamon-shy steel. This is not to say o1 does not produce a hamon, it just has a tendency to be a little more subdued. One way to bring out the hamon line is to polish the entire blade carefully, then etching this blade in boiling vinegar, then polishing it again carefully with the hamon line's representation in mind.

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interesting, thank you!

Thanks to both.

Learned a new word "patination". Woohoo!

I just want to add in on ferric chloride, it can be used in many ways. And the resulting polish will vary depending on what techniques you use before and after it. I feel I get best results with short light cycles, and I always polish away the "draggyness" it's oxides can produce. But yea I know many like to do long etches and sort of "set" almost a soot similar layer on the blade.

I think my favourite polish for myself, is polishing off almost all etching, for a discrete but lively hamon, but it's much less striking, most folks seem to want high contrast.

brooksie967 said:

Learned a new word "patination". Woohoo!

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Let me lay another one on you: Passivation: This refers to a material becoming "passive," that is, less affected or corroded by the environment of future use. Passivation involves creation of an outer layer of shield material that is applied as a micro coating, created by chemical reaction with the base material, or allowed to build from spontaneous oxidation in the air. As a technique, passivation is the use of a light coat of a protective material, such as metal oxide, to create a shell against corrosion.